What Causes Erectile Dysfunction?
The complete clinical guide — understand your specific cause before choosing a treatment
Erectile dysfunction is not a single condition — it is a symptom with multiple distinct underlying causes. The most important thing you can do before spending money on treatment is understand which type you have. A treatment that is highly effective for vascular ED may be useless for pharmacological ED, and vice versa. This guide explains every major cause and which treatments are evidence-based for each.
The most common root cause. Blood either can't reach the penis in sufficient volume, or can't be retained once an erection begins.
Arterial insufficiency
Reduced arterial blood flow due to atherosclerosis, hypertension, or diabetes. Responds well to Viagra and PDE5 inhibitors.
Responds to: Viagra, PRP, shockwave
Venous leak (veno-occlusive dysfunction)
Deep dive →Blood enters but veins fail to trap it. Erections soft or short-lived even with stimulation. Viagra often underperforms.
Responds to: PRP, shockwave, venous ligation (advanced)
The nervous system signal that triggers and maintains erection is disrupted — either centrally or at the penile nerve level.
Post-prostatectomy nerve damage
Deep dive →Prostate removal often damages cavernous nerves. Recovery depends on nerve-sparing technique and rehabilitation speed.
Responds to: PRP, vacuum erection device, penile rehabilitation
Diabetic neuropathy
Deep dive →Autonomic neuropathy from chronic high blood sugar damages the nerves governing erectile response.
Responds to: Blood sugar management, PRP, shockwave
Pelvic surgery / radiation damage
Bladder, colorectal, or other pelvic surgery can damage nearby cavernous nerves. Outcomes vary by nerve proximity.
Responds to: PRP, penile rehabilitation, implant
Hormonal imbalances affect both desire and the biological mechanisms of erection.
Low testosterone (hypogonadism)
Deep dive →Low T reduces libido, energy, and morning erections. May not cause ED directly but amplifies other causes significantly.
Responds to: TRT, lifestyle changes, PRP (complementary)
Hyperprolactinaemia
Elevated prolactin (from pituitary adenoma or medications) suppresses testosterone and causes ED.
Responds to: Dopamine agonist medication, treat underlying cause
Thyroid dysfunction
Both hypo- and hyperthyroidism can cause ED. Often overlooked in basic ED screening.
Responds to: Thyroid treatment, lifestyle correction
Many common medications cause ED as a side effect — often not disclosed to patients at point of prescription.
Antidepressants (SSRIs / SNRIs)
Sertraline, fluoxetine, paroxetine and similar drugs commonly cause ED and delayed ejaculation in 30–60% of men.
Responds to: Medication review, PDE5i addition, switch to different antidepressant
Antihypertensives (beta-blockers, thiazides)
Some blood pressure medications reduce penile blood flow or impair erectile mechanisms.
Responds to: Medication review, switch to ACE inhibitor or ARB class
5-alpha reductase inhibitors (finasteride, dutasteride)
Deep dive →Used for hair loss (Propecia) and BPH. Can cause persistent ED even after stopping — post-finasteride syndrome.
Responds to: Complex; see Post-Finasteride Syndrome page
Purely psychological ED is often misdiagnosed — most ED in men over 40 has a physical component even when anxiety plays a role.
Performance anxiety
A single failure creates anticipatory anxiety, which triggers adrenaline release that physically prevents erection. Cycle self-perpetuates.
Responds to: CBT, sex therapy, short-term PDE5i to break cycle
Depression
Depression reduces libido and impairs the neurological signalling for erection. Antidepressants can further complicate this.
Responds to: Treat depression; consider PDE5i concurrent with antidepressant
Relationship and stress factors
Chronic stress, relationship conflict, or unresolved emotional issues can suppress the parasympathetic response needed for erection.
Responds to: Couples therapy, stress management, psychosexual therapy
Mixed Aetiology: The Most Common Reality
Most men over 45 with ED have mixed aetiology — a combination of mild vascular impairment, perhaps a hormonal factor, and anxiety layered on top. This is why a single-treatment approach often underperforms: if you treat the vascular component but leave the hormonal or psychological component unaddressed, results are partial.
A thorough medical consultation will consider all possible contributing factors. Our doctor reviews each patient individually before recommending any treatment protocol.
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